Councils in Scotland are to be banned from making any attempts to shorten the length of the primary school week in a bid to save money, it has been revealed. 

The Scottish government is to change the law to make sure children spend a minimum of 25 hours a week in the classroom in a reaction to the belief that some councils were looking to reduce this in order to balance the books. 

In order to make sure changes can't be made to the working week for primary schools, ministers are looking to amend the Education Bill, which is currently before parliament. This currently states that schools must be open for 19 days a year, but it does not say how long they need to open for each day. 

The EIS teachers union has welcomed the move, but not everyone is happy at the news, with Cosla, the local government association angry that the Scottish government has moved to ban any future changes. 

One of the biggest controversies recently centred around Dunbartonshire local authorities, where it was agreed in February that two and a half hours of the school week would be cut. If enacted, this would see £1 million saved over the course of the year. 

Highland Council also floated the idea of having a four and a half day week for primary school children in a bid to save funds, and this week, its councillor Bill Fernie said: "There is not any evidence which links better education attainment to a 25-hour school week and this would put further pressure on local authority budgets and our ability to make the necessary savings required to manage the anticipated cut in grant funding."

Education secretary Angela Constance said of the changes that the Scottish government is currently doing all it can to "deliver both excellence and equity for every child". 

"We are driving a relentless effort to boost educational achievement and, critically, to make quicker progress in closing the attainment gap, for example through the £100m Scotland Attainment Challenge," she said. 

"Scotland's teachers are absolutely critical to these efforts. That's why we have committed investment of up to £51m this year specifically to help local authorities to maintain teacher numbers. 

"And it's why we will legislate to provide certainty for pupils, parents and teachers about the length of the school week - a teacher time guarantee that every one of our children and young people should expect, and which they deserve."